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Module 22
Rev. 10/2013
Module 22: Subsidence Control and Underground Mine Maps
Instructions: Information submitted under this Module must be certified by a licensed professional engineer or a
licensed professional land surveyor.
Note:
That at a minimum, the subsidence control plan shall address all areas within a 30-degree angle of draw of
underground mining which will occur during the five (5)-year term of the permit.
22.1
Subsidence Control Plan.
a. Describe the equipment to be used for development and retreat phases of mining.
b. State the range of proposed mining centers for entries and crosscuts within the mains, submains, butts,
rooms, etc.
c.
d.
State the average and maximum proposed entry and crosscut widths. These must be specific to the
various entries and crosscuts to be used throughout the mine - such as mains, submains, butts, rooms,
belt and track entries and any other areas in which the entry and crosscut width may vary.
Provide a description including sketches, if necessary, indicating the method of secondary or retreat
mining to be used. The description should address the following, as applicable:
i.
Method of mining (pillar recovery, slabbing, splitting, longwall, shortwall, etc.);
ii.
The sequence of pillar recovery;
iii.
The sequence and widths of cuts, slabs, or splits;
iv.
Configuration of remaining pillars, fenders, or stumps, etc.
v.
The range of the length and width of the longwall panels.
e. State the proposed extraction percentages for mains, submains, butts, rooms, etc. for development and
retreat phases.
f.
Describe whether subsidence, if it is likely to occur, could cause material damage to any structure or
could adversely affect any water supply.
g. Describe in detail how mining activities will be planned and conducted to not cause material damage or
reduce the reasonably foreseeable use of the following features as present within the subsidence control
plan area:
i.
Noncommercial structures commonly used by the public such as churches, schools, and hospitals;
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ii.
Public facilities such as government office buildings, police stations, prison complexes, municipal
swimming pools, municipal utilities, public water lines, municipal airports, public park pavilions and
maintenance facilities;
iii.
Impoundments or other bodies of water with a storage capacity of 20 acre-feet or more;
iv.
Bodies of water or aquifers that serve as significant sources of public water supply.
h. Describe the measures to be taken to minimize damage, destruction, or disruption of services to the
following items as present within the subsidence control plan area or provide information showing that
facilities will not be damaged. The description must address notification procedures, agreements and
precautionary measures (at the land surface or in the mine).
i.
i.
Gas wells and oil wells;
ii.
Water wells (wells which penetrate the target coal seam must have a block of coal around them);
iii.
Oil, gas, and coal slurry pipelines (if necessary mining is proposed, the type, use, pressure,
composition, and approximate age of the gas pipeline must be included);
iv.
Rail lines;
v.
Electric and telephone lines; and
vi.
Water and sewerage lines.
Describe any applicable subsidence control measures required to satisfy the following statutes:
i.
Act of December 22, 1959 (Act No. 729, Mining in Safety Zones);
ii.
Oil and Gas Act (58P.S. §§601.101-601.605)
iii.
Section 419 of the State Highway Law (Act No. 428); and
iv.
Act of June 1, 1933 (Act No. 296, State Mining Commissions).
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Describe how proposed mining will serve to maximize the stability of the workings that will remain when
mining is complete. Discuss various scenarios of mining height, extraction percentage, and cover
thickness as necessary to cover the range of conditions that will be encountered in the underground
permit area. Describe the anticipated effects of planned subsidence.
i.
For settings where pillars will be left in place, provide calculations to show their ability to provide
continual support to the overlying strata; or the results of a geotechnical investigation of a
previously mined area where equal or smaller pillars proved to be stable.
ii.
If mining will take place under less than 100 feet of cover, also provide assessment of roof stability.
iii.
For settings where final mine stability will be achieved by removing enough coal to induce roof
collapse, provide calculations to show that remaining stumps will lack the ability to support the
overlying strata, or the results of a geotechnical investigations showing that stumps of equal or
larger size failed within a few years of mining. (If longwall mining will be conducted, simply state "Longwall Mining" in response to this item.)
k.
Describe the methods that will be used to mitigate subsidence damage that may occur (purchase,
restoration, compensation, etc.). Provide a statement affirming that damaged structures will be repaired
or replaced, or that the structure owner will be compensated for the cost of the repair or replacement. If
secondary mining will occur beneath dwellings, barns, or silos, include a description of the measures to
prevent irreparable damage to these structures if the structure owner does not concur to allow
irreparable damage.
l.
If an operator employs a mining technology that provides for planned subsidence in a predictable and
controlled manner, describe the necessary and prudent measures that will be used to minimize material
damage to the extent technologically and economically feasible to the structure(s).
m. If an operator employs a mining technology that does not result in planned subsidence in a predictable
and controlled manner, describe the necessary and prudent measures that will be used to prevent
subsidence and subsidence-related damage to the extent technologically and economically feasible to
the structure(s), describe the measures that will be taken to prevent subsidence-related adverse impacts
to places listed or eligible for listing, on the National Register of Historic Places and archaeological
resources.
i.
For mining that is proposed beneath structures where the depth of overburden is less than
100 feet, include a description of the site characteristics and/or mining techniques, which will
ensure stable mine workings and prevent irreparable damage to overlying structures. Describe the
measures to be taken to maintain the value and reasonably forseeable use of surface lands.
ii.
Describe the measures that will be used to correct any subsidence-related damage to surface
lands. Describe the measures to be taken to maintain the value and reasonably forseeable use of
surface lands.
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iii.
Indicate whether the mine has caused irreparable damage to any dwelling or agricultural structure
listed under 89.142a or if it is likely to cause such damage. If irreparable damage is likely to occur,
indicate the measures that will be used to prevent that level of damage should the structure owner
not consent.
iv.
Describe any monitoring that will be performed to prevent, reduce, identify, or correct subsidencerelated damage.
Geologic Considerations
a. Describe the minimum, maximum, and average cover conditions within the subsidence control plan area.
b. Describe the minimum, maximum, and average mining height within the subsidence control plan
boundary.
c.
Discuss the geologic factors which may serve to cause, prevent, or otherwise influence the following:
i.
Height and form of caving;
ii.
Pillar failure;
iii.
Pillars punching into mine floor or roof; and
iv.
Floor heave.
d. Describe any site-specific geologic conditions which are relevant to the likelihood or extent of subsidence
related damage.
22.3
Index Map
Provide a 7.5 minute USGS map that shows the underground permit area and index to the six-month map
series. Include a legend containing the map title, mine name, company name, coal seam, township, county,
scale, engineer’s (or surveyor’s) signature, and seal. Show the following:
a. Boundary of the underground permit area;
b. Boundary of the subsidence control plan area;
c.
A sheet index for the six-month maps;
d. A sheet index for the subsidence control maps (Module 22.4 map).
22.4
Subsidence Control Plan Map (see mapping standards in Module 22.9)
Provide a subsidence control plan map at a scale of 1 inch = 500 feet or larger, showing the information
listed in this section. Include either a north arrow or coordinate grid system for orientation; and a legend
containing the map title, mine name, company name, coal seam, township, county, scale, index sheet
number, engineer’s (or surveyor’s) signature and seal. The map must include all areas where structures or
perennial streams may be impacted by underground mining activities. At a minimum, the map must cover
the area determined by projecting a plane along a 30-degree angle upward and outward from the limits of the
planned coal extraction area. However, all adjacent underground mine workings within 1,000 feet of the
proposed mine must be shown.
a. The boundaries of the underground permit area and subsidence control plan area.
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b. Coal barriers to be maintained around the perimeter of the underground permit area.
c.
A mining forecast showing the size and sequence of incremental mining areas over the life of the
operation.
i.
For areas within the subsidence control plan boundary, the forecast must be in yearly increments
(i.e., Year 1, Year 2, etc.) with single line projections indicating proposed main, submain, and butt
headings, gate entries and longwall panels.
ii.
For areas outside the subsidence control plan boundary, the remaining parts of the mine plan may
be shown by outlining proposed mining areas in increments of five (5) years or less. Mine life must
be consistent with Module 10.1a.
d. Structures, features and resources relevant to subsidence control plan development, including:
i.
The boundaries of lands and names of current surface and coal owners of record.
Module 5.)
(Key to
ii.
Dwellings, public buildings and facilities, churches, schools, hospitals and impoundments with a
storage capacity of 20 acre-feet, identified by numerical reference.
iii.
Buildings that are accessible to the public including, but not limited to commercial, industrial and
recreational buildings and all permanently affixed appurtenant structures identified by numerical
reference.
iv.
Noncommercial buildings that are customarily used by the public, and not listed in Item iii,
identified by numerical reference.
v.
Dwellings that are used for human habitation and permanently affixed appurtenant structures and
improvements. (Identify any improvements that are not subject to repair requirements because
they were not in place on August 21, 1994 or on the date of first publication of the most recent
permit or permit renewal application.)
vi.
Barns and silos identified by numerical reference.
vii.
Permanently affixed structures of 500 or more square feet in area that are used for raising
livestock, poultry or agricultural products, for storage of animal waste or for the processing or retail
marketing of agricultural products on the farm on which the structures are located identified by
numerical reference.
viii.
Public parks and historic structures.
ix.
Structures which are entitled to support by law or agreement, identified by numerical reference.
x.
Water supply wells identified by numerical reference.
xi.
Water supply springs identified by numerical reference.
xii.
Major electric transmission lines, including identification by name or numerical reference.
xiii.
Public roads by route number, and railroads.
xiv.
Oil, gas and coal slurry pipelines larger than four inches in diameter, including identification by
name or numerical reference.
xv.
Water and sewer mains and transmission lines, including identification by name or numerical
reference.
xvi.
Surface water bodies, including perennial streams, lakes, ponds, dams and impoundments with a
volume of 20 acre-feet or more, indicating by numerical reference those perennial streams and
other bodies of water which are a significant source for a public water supply system.
xvii. Coal refuse disposal areas, solid and hazardous waste disposal areas, and other air and water
pollution control facilities, all identified by name or numerical reference.
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xviii. Gas, oil and water wells.
xix.
Surface sites and facilities associated with the underground permit application.
xx.
Political subdivisions.
xxi.
Landslide prone areas.
xxii. Areas over the proposed mine where the overburden is 100 feet or less.
xxiii. Coal seam contours.
xxiv. All historical or existing sealed mine openings (including boreholes), as well as all proposed mine
openings within the permit area.
e. Identify in a distinguishing manner those structures, features and facilities that must be protected against
material damage or reduction in reasonably foreseeable use in accordance with 89.142a(c), including:
22.5
i.
Churches, schools and hospitals.
ii.
Public buildings, facilities, and water lines.
iii.
Impoundments with a storage capacity of 20 acre-feet or more.
iv.
Bodies of water with a volume of 20 acre-feet or more.
v.
Bodies of water or aquifers that serve as significant sources to a public water supply system.
vi.
Perennial streams that serve as significant sources to a public water supply system.
Public Notice (89.144)
Provide examples of notification letters that will be sent to property owners, residents, and local government
offices. A copy of each notice will be required at a later date to coincide with six-month map reviews. (Note:
transfer applicants must re-notify parties who have yet to be undermined even though they were notified by
the previous permittee.)
22.6
Six-Month Projection Maps (see mapping standards in Module 22.9)
Six-Month Projection Maps and the Index Map (Module 22.3) must be submitted to and accepted by the
Department before underground mining begins. However, these maps need not be submitted with the initial
permit application. The six-month maps must be on a scale of not less than 1 inch = 200 feet and must
include, at a minimum, the information listed in Modules 22.4.d and 22.4.e.
The following information must also be included on six-month maps where an applicant chooses to submit
"combined maps" that will satisfy mapping the requirements under the Bituminous Coal Mine Act as provided
for under the Department's Technical Guidance 563-2000-610:
a. All openings, excavations, shafts, slopes, drifts, tunnels, planes, main entries, cross entries and rooms
and the name or number of each;
b. The direction of air currents, indicated by arrows, with each split numbered and suitably designated;
c.
Elevations of the top and bottom of each shaft and slope, of all drifts, tunnels, planes and of the faces of
entries including the number of last survey station and the date of such survey;
d. Location and elevation of any body of water dammed in the mine, or held back in any portion of the mine.
(Note: Gas wells are required to be shown on Six-Month Projection Maps, therefore, the applicant is
reminded to contact the appropriate regional Oil and Gas Management office to obtain this information).
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22.7
Rev. 10/2013
Structure Inventory
Provide a list of all surface owners and structures, facilities and features identified by numerical reference
located within the subsidence control plan boundary and within a 30-degree angle of draw projected from
that boundary. List properties and structures in order of their identification numbers and provide the following
information:
a. Surface owner name and address;
b. Parcel number or tax identification number associated with each surface (use a period “.” to separate the
parcel number or tax identification number (ex. “12.345.5678”).
c.
A unique structure identification number;
d. Type or use of structure;
e. Identify each structure to which damage must be prevented; and
f.
22.8
Map sheet (1 inch = 100 feet or 1 inch = 200 feet map set) on which structure appears.
Property Assessment Data
Provide the total tax assessment value of all properties within the subsidence control plan boundary and
within a 30-degree angle of draw projected from that boundary.
22.9
Mine Map Standards
It is extremely beneficial for all mining operations in a given area to be tied into the same standardized
coordinate system. This minimizes problems along boundaries and at mine connections. Additionally, this
system must be tied into and made part of the state grid system. Therefore, the following minimum
standards shall be adhered to for mine maps:
a. Minimum angular and coordinate ties for raw data would be an angular tie of less than 00˚01’00’’
(1 minute) and a coordinate tie of greater than 1:10,000 (1 foot in 10,000 feet) for any given closed loop
survey.
b. A closed loop survey is required to be at the next to last open crosscut of the mining section, but not
more than 100 feet from the final face of a mining section.
c.
Elevation closure of +/- 0.01 feet per 5,000 feet.
d. Vertical elevation shall be based on mean sea level (USGS elevation).
e. Preferred datum is the Pennsylvania State Plane coordinate system (NAD83 Datum).
f.
22.10
Where applicable, appropriate coordinate transformation equation(s) should be placed on the map.
Adjacent Mine Working(s)
Utilize any and all sources necessary to accurately determine the full extent and location of adjacent
abandoned mine workings. Document the types of sources used on the attached Form 22.10 which provides
a check list of potential sources. Document any additional sources utilized in the form’s blank spaces.
Provide a narrative summary of all information used and the steps taken to obtain that information. At a
minimum, the summary should address the following types of information:
a. Identification of all data sources used to verify and validate mine maps as documented on Form 22.10;
b. Listing of all mine map repositories searched during the research process;
c.
Procedures used to orient and locate nearby abandoned mine workings with respect to the proposed
mine;
d. A description of and results of field reconnaissance used to delineate mine workings;
e. Identification of all maps found in the search and relied upon to map abandoned mine workings,
including ID or catalog numbers, archive location, scale, and condition;
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Local gas well or water well drill logs that may indicate the presence of absence of mine voids;
g. Underground mine inspection records;
h. Annual coal production report data, including mine opening date and last coal extraction;
i.
Permit information cross-checks with the Bureau of Mining and Reclamation;
j.
Mechanical, geologic, or geophysical testing used to verify the mine workings, such as vertical or
horizontal drilling or geophysical surveying;
k.
An operational history of each adjacent abandoned mine including all ownership changes, dates of
operation, dates when the mine was idle, date of mine closure, mine name changes, coal company
name changes, and all permit identification numbers including an explanation showing that the map
corresponds to the data found in the history;
l.
An explanation of how mine pool elevation data for each abandoned mine was determined;
m. A discussion of any disparities between sources of information including site-specific details provided by
local residents
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Form 22.10
Recommended Sources of Mine Map Information
In order to validate mine void location information provided to the Department, an applicant for an underground mine
permit should use all sources necessary to accurately ascertain the full extent and location of adjacent abandoned
mine workings. Potential sources of useful information are listed on the following checklist. Additional space is
provided to add additional sources as needed.
Information Source
Place a check (√) next to
each information source
relied upon to validate
location of mine workings
Date that
Source
Review was
Completed
Coal production records
Tax records
Local Driller’s logs (gas and water)
Worker’s compensation records
County property records
Employment records
Newspaper accounts
Public mine map archives
(Pennsylvania Geologic Survey, OSM,
Pa. Deep Mine Safety, Pa. District
Mining Operations)
Private mine map archives (local coal
companies, museums and universities)
Museums
Local citizens
Field reconnaissance
Universities
Libraries
State Mine Inspector’s records
Federal Mine Inspector’s records
Operational histories of local mining
companies
Survey data – notes, traverse books,
sheets, etc…
Applicant’s Signature
Date
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Reviewer’s
Initials